Angiosperms can be grouped into monocots and dicots according to the number of cotyledons they possess.
Bean seeds have 2 cotyledons, which contain the stored food reserves of the seed.
The embryo develops between the cotyledons. Its two main parts are the plumule and the radicle. The former grows into the root of the new plant, while the latter develops into the stem and the leaves, that is, the shoot.
Maize, or corn, is a monocotyledon, that is, its seed contains only one cotyledon. Its function is to transportnutrients from the endosperm to the embryo. The endosperm stores the food required for the development of the embryo, which, in case of maize, is starch. We can easily observe the embryo in the maize seed, with the plumule and the radicle.
During germination, the seed absorbswater and swells. Then the pericarpopens and the radicle starts to develop into the root. In dicots the developing plumule pushes cotyledons abovetheground, while in monocots the cotyledon stays underground.